Skip to main content

Purple Deadnettle

David Workman, WVU Extension Agent – Agriculture and Natural Resources

Many folks are noticing a purple flowering plant appearing in yards, gardens and fields.  These are most likely Purple Deadnettle or Henbit.  These are winter annuals and part of the mint family that are present in normal years.  Being winter annuals, they have a shallow root system and typically complete their life cycle before growing season.  They may be more noticeable during winters with more moderate weather conditions.

According to WVU Extension Weed Specialist Dr. Rakesh Chandran, “this mild winter seasons allow these weeds to get a head-start on the grass and other species.”

These flowering plants do provide an early feed source for our pollinators.  Bees that are getting active at this time of year are attracted to the flowers on these plants for nourishment.  It is important that we protect our pollinators as they do important work in the field and garden.

Control Measures

Chandran indicated there are several options to consider to address these “weeds” depending on the situation.

Lawn

In lawns, the Purple Deadnettle and Henbit can compete for space with desired grass species.  Bare spots left behind may allow summer annuals, such as crabgrass, to take over. The options include hand-weeding or mowing small areas and chemical treatment for larger areas.  Q4 is an effective herbicide that controls actively growing winter annuals in lawns. 

Since most of these winter annuals germinate during the preceding fall, application of a pre-emergence herbicide in September/October could result in a lawn relatively weed-free during the following spring. Applying an effective herbicide during that time could help control other pesky summer weeds such as dandelions, white clovers, plantains and crabgrass the following year. Therefore, fall is the best time for homeowners to consider a treatment for these unwanted plants and the results will be noticed the following year.

Homeowners may consider reseeding any bare spots with desirable grass species.  Again, fall (September) is a good time of the year to do so, followed by spring (April).  A soil test is recommended and the WVU Extension Service or West Virginia Department of Agriculture can assist with soil testing.

Small Home Gardens

In small home gardens, tillage will likely offer the best control measure. Tilling or cultivation will reduce the production of seeds, facilitate the warming up of soils and trigger germination of other weed seeds.  After leaving such areas stale for a few weeks, a light secondary cultivation will control additional weeds after which the crop can be planted and mulched to prevent further weed competition.  It may not be necessary to apply herbicide products in home garden settings due to plant sensitivity.

Fields

In fields that are cultivated or prepared for field crops, Purple Deadnettle and Henbit are not generally a concern.  Since most herbicide packages for field crops employed in either burndown or post emergent treatments should be sufficient to control these unwanted plants.

As always read the label and follow all directions for use of any products applied to lawns, gardens or fields for control of unwanted pests.

For more information on these plants or recommendations, contact your local WVU Extension Service Office.